Method and circuit arrangement for controlling the temperature of AC-operated heating devices

摘要

The invention relates to a method and a circuit arrangement for controlling the temperature of AC-operated heating devices, in particular of heating pads, heater blankets or the like. The heating devices are provided with a single-part or multi-part heating conductor (1), furthermore with a temperature-dependent switching member (2) which is connected in series thereto and is thermally connected to the heating conductor (1), and with an actuator (3) for presetting the desired temperature. In the one flow direction of the current, the supply voltage drops essentially completely across the heating conductor (1), and in the opposite flow direction of the current it drops for a large part across a pre-heating resistor (6). The pre-heating resistor (6) is in thermal interaction with the temperature-dependent switching member (2), the current flow in the opposite flow direction being switchable and/or variable by means of the actuator (3). <IMAGE>